解决ajax提交到后台数据成功但返回不走success而走的error问题

 $("#sourcefile").ajaxSubmit({ 
  type: "post", 
  dataType: "json", // 'xml', 'script', or 'json' (expected server response type) 
  url: "/springMVC/upload/up", 
  success: function (result) { 
 	 if (result) { 
 		 alert(result.col0);
 	 }
	 	 
  }, 
  error:function(data, XMLHttpRequest, textStatus, errorThrown){ 
 	alert(1); 
 	 } 
 }); 

 @RequestMapping(value="/upload/up")
 
 public @ResponseBody ExcelName upload(@RequestParam("sourceFile") MultipartFile sourceFile, HttpServletRequest request, ModelMap model,HttpServletResponse response) { 
 	 //判断文件是否为空
 if (sourceFile==null) return null;
 //获取文件名
 String name=sourceFile.getOriginalFilename();
 System.out.println("name");
 //进一步判断文件是否为空（即判断其大小是否为0或其名称是否为null）
 long size =sourceFile.getSize();
 if (name==null ||("").equals(name)  size==0) return null;
 
 //批量导入。参数：文件名，文件。
 ListExcelName> cpolicyList = ExcelUtils.batchImport(name,sourceFile);
 //迭代添加信息（注：实际上这里也可以直接将cpolicyList集合作为参数，在Mybatis的相应映射文件中使用foreach标签进行批量添加。）
 for( ExcelName customer:cpolicyList){
 	colDataService.insertData(customer);
 } 
 
 ExcelName e1=new ExcelName();
 e1.setCol0("success");
 return e1;
｝

%@ page language="java" contentType="text/html; charset=utf-8"
 pageEncoding="utf-8"%>
!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
html>
head>
meta http-equiv="Content-Type" content="text/html; charset=utf-8">
title>上传/title>
script type="text/javascript" src="./jquery-3.1.1.js">/script>
script type="text/javascript" src="./jquery.form.js">/script>
script type="text/javascript">
 
function submitImport(){ 
 var epath = $('#source_file').val(); 
  
 if(epath==""){ 
  alert( '导入文件不能为空!'); 
  return; 
 } 
 
 if (epath.substring(epath.lastIndexOf(".") + 1).toLowerCase()!="xlsx") { 
  alert( '导入文件类型必须为excel!'); 
  return; 
 } 
 
 $("#sourcefile").ajaxSubmit({ 
  type: "post", 
  dataType: "json", // 'xml', 'script', or 'json' (expected server response type) 
  url: "/springMVC/upload/up", 
  success: function (result) { 
 	 if (result) { 
 		 alert(result.col0);
 	 }
	 	 
  }, 
  error:function(data, XMLHttpRequest, textStatus, errorThrown){ 
 	alert(1); 
 	 } 
 }); 
} 
//partExport
function downloadTemplate() { 
	document.sourcefile.action = "/springMVC/upload/partExport";
 form.submit(); //表单提交
 }
 
 
/script>
/head>
body>
div>
 form id="sourcefile" name="sourcefile" action="" method="post" enctype="multipart/form-data">
 input type="button" value="添 加" onClick="addAirLine()" />
 input style="margin-left: 20px;" id="source_file" name="sourceFile" type="file" value="选择文件" />
 input style="margin-left: 20px;" data-loading-text="请勿重复提交" type="button" value="上 传" onClick="submitImport()">
 input style="margin-left: 20px;" type="submit" value="下载模板" onClick="downloadTemplate();">
 /form>
 /div>
/body>
/html>